Superstereoscopic display with enhanced off-angle separation

ABSTRACT

A superstereoscopic display with enhanced off-angle separation includes a first light source; a lenticular lens optically coupled to the first light source that, with the first light source, generates a first light output having viewing angle dependency; and a high-index optical volume optically coupled to the lenticular lens.

CROSS-REFERENCE TO RELATED APPLICATIONS

This invention is a continuation of U.S. patent application Ser. No.16/044,355, filed on 24 Jul. 2018, which claims the benefit of U.S.Provisional Application No. 62/635,728, filed on 27 Feb. 2018, and ofU.S. Provisional Application No. 62/661,605, filed on 23 Apr. 2018, allof which are incorporated in their entireties by this reference.

TECHNICAL FIELD

This invention relates generally to the image display field, and morespecifically to new and useful superstereoscopic displays with enhancedoff-angle separation.

BACKGROUND

Image displays are an integral part of modern life. From televisions tomonitors to smartphone and tablet screens, image displays provide userswith the ability to view and interact with information presented in avariety of forms.

The advent of three-dimensional displays has enabled users to experienceimages with higher realism than would be possible with theirtwo-dimensional counterparts; however, the vast majority of 3D displaysrequire the use of a head-mounted display (HMD) or other cumbersomeperipheral.

Free-space 3D displays remove the need for an HMD, allowing multipleusers to see and manipulate content in a shared experience.Unfortunately, the few existing free-space 3D displays are hampered by anumber of issues, including size, limited view angle, low resolution andbrightness, scene distortion, and high cost. Thus, there exists a needin the image display field to create new and useful superstereoscopicdisplays with enhanced off-angle separation. This invention providessuch new and useful displays.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a top-down view of a display of an invention embodiment;

FIGS. 2A and 2B are stereoscopic views of a three-dimensional image;

FIGS. 3A and 3B are cross-sectional views of a display of an inventionembodiment;

FIG. 4 is a cross-sectional view of a parallax generator of a display ofan invention embodiment;

FIG. 5A is a cross-sectional view of a lenticular lens in a stretchedconfiguration of a display of an invention embodiment;

FIG. 5B is a cross-sectional view of a lenticular lens in a compressedconfiguration of a display of an invention embodiment;

FIG. 6A is a light path view of an image projected from a light sourceof a display of an invention embodiment;

FIG. 6B is a light path view of an image projected from a light sourceand passing through a high-index optical volume of a display of aninvention embodiment;

FIG. 7 is a top-down view of a display of an invention embodiment;

FIG. 8 is a perspective view of a high-index optical volume andperceived additional volume of an invention embodiment;

FIGS. 9A, 9B, and 9C are various perspective views of a display of aninvention embodiment; and

FIGS. 10A and 10B are top-down views of image view dependency on viewingdistance of a display of an invention embodiment.

DESCRIPTION OF THE INVENTION EMBODIMENTS

The following description of the invention embodiments of the inventionis not intended to limit the invention to these invention embodiments,but rather to enable any person skilled in the art to make and use thisinvention.

1. Superstereoscopic Display with Enhanced Off-Angle Separation

A superstereoscopic display 100 with enhanced off-angle separationincludes a light source 110, a parallax generator 120, and a high-indexoptical volume 140, as shown in FIG. 1. The display 100 may additionallyor alternatively include polarizers 130, quarter waveplates 131, opticalvolume guides 141, an onboard computer 150, and/or a contextual lightingsystem 160.

As shown in FIG. 1, the display 100 functions to enable viewers to seetwo- and/or three-dimensional image data from multiple perspectives atthe same time. The display 100 generates an angle-dependent viewingexperience, which can be used to provide a three-dimensional viewingexperience (via stereopsis) and/or to provide viewers at differentangles with different images depending on viewing angle (withoutnecessarily causing the perception of depth). An example is as shown inFIGS. 2A and 2B. While the display 100 is capable of producing the same3D image at multiple angles (e.g., viewer 1 has eyes at 0 and 5 degrees,which see image 1 and 2 respectively; viewer 2 has eyes at 20 and 25degrees, which see image 1 and 2 respectively), the display 100preferably produces a continuous unbroken scene (e.g., image 1 at 0degrees, image 2 at 5 degrees . . . image N at 5(N−1) degrees where N isan integer) 100 better provide an immersive viewing experience.Alternatively, the display 100 may utilize any set of images for anypurpose.

Enhanced off-angle separation is preferably enabled by the high-indexoptical volume 140; by nature of its high index of refraction and shape,the optical volume 140 may cause the primary image(s) intended for aviewer at a particular viewing angle to appear closer to the viewer thanotherwise would occur (without the optical volume 140), increasing theperception that the image produced by the light source no “floats” offof the screen. Further enhancing this effect, for images off-axis to theviewer at a particular viewing angle, the images may not appear as closeas on-axis images do, appearing to the viewer to separate on- andoff-axis images in space. This phenomenon is discussed in greater detailin the section on the high-index optical volume 140.

The light source 110 functions to generate images (i.e., light generatedfrom image data) for display by the display 100. The light source 110 ispreferably a planar two-dimensional display comprising a set ofindividually addressable pixels, but may additionally or alternativelybe any suitable display. For example, the light source no may compriseone or more movable light sources; e.g., a laser that may be scannedacross a set of positions to simulate the appearance of multiple lightsources (i.e., display multiplexing).

The light source 110 is preferably an RGB color light source (e.g., eachpixel includes red, green, and blue subpixels) but may additionally oralternatively be a substantially monochromatic light source or any otherlight source (e.g., a white light source).

The light source 110 is preferably a projector or projector light engine(e.g., DLP, laser, LCoS, and/or LCD projector) but may additionally oralternatively be any suitable display (e.g., an LCD monitor/TV display,an OLED display, an e-ink display, an LED array, a spinning LED display,an e-ink display, an electroluminescent display, a neon display, etc.).In one variation of a preferred embodiment, the light source 110includes a liquid crystal panel with a collimated backlight.

The display 100 preferably includes a single light source 110, but mayadditionally or alternatively include multiple light sources 110. Forexample, multiple light sources 110 may be placed in series and/or inparallel as shown in FIG. 3A and FIG. 3B respectively. Note that anycombination of light sources 110, polarizers 130, quarter-waveplates131, and/or additional optics (e.g., mirrors, lenses, etc.) may be usedin the display 100. In configurations utilizing multiple light sources110, the light sources 110 may be offset, angled, rotating, curved, orotherwise configured in any manner.

The light source 110 may include optical elements (e.g., lenses,mirrors, waveguides, filters) that function to couple light into theparallax generator 120 and/or the high-index optical volume 140. Forexample, the light source no may include a collimating lens designed toincrease collimating of the light source 110 output. As a secondexample, the light source no may include a lens designed to scale (orotherwise distort) light source no output (e.g., reduce in size orincrease in size). Such a lens may scale light source no outputuniformly (e.g., 2× decrease in both image dimensions) or non-uniformly(e.g., no decrease in first image dimension, 4× decrease in other imagedimension). As a third example, the light source no may include a lensthat manipulates the focal plane of the viewed image; such a lens may betunable (allowing depth of field to be swept). If such a lens is tunableat a high rate, this may provide an expanded perceived depth of field toa viewer.

The light source 110 may additionally or alternatively include anypassive or active optical elements to prepare light for use by thedisplay 100 for any other purpose. For example, the light source no mayinclude filters or splitters. As a more specific example, the lightsource 110 may include a polarizing filter if the native output of thelight source no is unpolarized. As another example, the light source nomay include microlens arrays and/or Fresnel lenses.

The parallax generator 120 functions to generate an angle-dependent viewfrom the light source 110 output. The parallax generator 120 may be anystructure capable of generating such an angle-dependent view (e.g.,lenticular lenses, micro-spherical lenses, parallax barriers, etc.).

In a first example, the parallax generator 120 is a lenticular lens. Thelenticular lens generates an angle dependent view in combination with alight source no that displays different pixels (or image segments) basedon the positioning of the lenticular lens over the light source 110. Forexample, as shown in FIG. 4, the image shown to viewers at three anglesis comprised of the pixels labeled 1, 2, and 3, respectively.

Based on the properties of the lenticular lens (e.g., pitch, material,structure, orientation and position relative to the light source no) anddesired viewing characteristics (e.g., number of viewers, view distance,number of views desired, viewing mode, etc.), the display 100 may modifythe output of the light source 110 to produce a desired result.

In one example embodiment, the number of different views provided by thedisplay 100 is sufficient for superstereoscopic viewing at some viewingdistance; that is, each eye of the viewer receives a different imagefrom the display 100, and as the viewer moves around the display 100,the views change (with the viewing angle). For example, a viewer atangle one may see scene 1 with a right eye and scene 2 with a left eye,where scene 1 and scene 2 create a stereoscopic three-dimensional viewof one or more objects. After the viewer moves from angle one to angletwo, the viewer now sees scene 2 with the right eye and scene 3 with theleft eye, producing a second stereoscopic three-dimensional view of theone or more objects. In this manner, the viewer perceives athree-dimensional image (thanks to the stereoscopic effect) at a givenviewing angle, and that perception is preserved (thanks to the changingviews, which correspond to a rotated view of the one or more objects) asthe viewer moves around the display 100, as shown in FIG. 2A(corresponding to a first view) and FIG. 2B (corresponding to a secondview). A display that produces more than one stereoscopicthree-dimensional view in this manner may be referred to as asuperstereoscopic display.

The lenticular lens may have any suitable configuration and structureand may be made of any suitable material. The lenticular lens ispreferably one-dimensional (e.g., cylindrical lenses arranged incolumns), but may additionally or alternatively be a two-dimensionallenticular lens, fly-eye lens array, or integral imaging lens array.Note that while there is preferably a correlation between addressablesegments (e.g., pixels) of the light source 110 and the lenticular lens,the lens columns of the lenticular lens need not be at a particularorientation relative to the light source no. For example, while columnsof the lenticular lens may be aligned with pixel columns, they may alsobe offset at an angle (which allows the resolution loss due to imageslicing to be apportioned across both image pixels columns and rows,rather than only one of these). This technique is described further inU.S. Pat. No. 6,064,424. Image slicing or division (of light source 110output) may be accomplished in any manner to achieve a desired viewingresult. Processing of the image is preferably performed by the onboardcomputer 150 but may additionally or alternatively be controlled by anycomputer system.

Note that lenticular lenses may be reconfigurable to change the opticalproperties of the lenses. For example, a lenticular lens may befabricated of a flexible or semi-flexible material so that the lens canbe physically compressed or stressed to change the pitch of the lens, asshown in FIGS. 5A (stretched) and 5B (compressed), and the pixel-to-lensmapping may be changed accordingly. Additionally or alternatively, theoptical properties of the lens may be altered by another mechanism(e.g., by modifying the index of refraction of the lenticular lens). Asanother example, a lenticular lens may be implemented using a layeredliquid crystal array (either as the entire lens or in conjunction with afixed refractive lens), enabling dynamic configuration of the lenticularlens.

The display 100 may include multiple lenticular lenses and/or otherlenses to produce a desired optical effect. For example, 1D lenticularlenses may be stacked at different orientations to create 2D angularview dependence.

In a second example, the parallax generator 120 is a pinhole array orparallax barrier. In a third example, parallax generation may beprovided by multiple light sources no. For example, a set of projectorsat different angles and a viewing angle-dependent film or surface(together functioning as both the parallax generator 120 and the lightsource no) may be used to produce a similar viewing effect to a singlelight source no and an overlaid parallax generator 120.

Polarizers 130 and quarter waveplates 131 may be used to enhance thequality of the image output of the display 100. For example, in theconfiguration as shown in FIG. 1, the polarizers 130 and quarterwaveplate 131 may increase perceived image contrast or brightness (bysuppressing errant reflection). This same effect may be used, forexample, to reduce any image ghosting caused by the parallax generator120 (in this case, the ‘ghost’ images may be of a different polarizationthan intended/on-axis images).

While polarizers 130 and quarter waveplates 131 may be laminated ontothe optical volume 140, it may be desirable for these (and other)optical components to be separated by some material (or air/vacuum) inorder to prevent the loss of light from the optical volume 140 that mayresult from frustrated total internal reflection (FTIR) since thepolarizers 130/quarter waveplates 131 may have an index between that ofthe optical volume 140 and the surrounding air.

The high-index optical volume 140 functions to enhance viewing of thedisplay 100 by enhancing perceived separation between on-angle views(i.e., primary views) and off-angle views.

The high-index optical volume 140 is preferably a solid rectangularprism of an optically clear material (e.g., acrylic, glass,polycarbonate), but may additionally or alternatively be anythree-dimensional volume (made of any materials in any structure)capable of transmitting light and having an index of refraction greaterthan one. For example, the high-index optical volume may be acrylic andhave a relative index of refraction of 1.49.

As shown in FIG. 6A, by itself, a light source no can create an image onthe eye of a viewer. After incorporating the high-index optical volume140, the image formed on the viewer's eye is smaller, suggesting thatthe perceived image with the optical volume 140 in place is eithercloser (e.g., as shown by the perceived location of image) or largerthan it would be without optical volume. Given appropriate relative sizeclues (e.g., physical boundaries of the display) it is likely that aviewer may perceive the image as closer (e.g., ‘floating’ within theoptical volume 140), as shown in FIG. 6B. The optical volume 140 mayhave the additional benefit of increasing viewing angle of the display100 (by bending light toward on-axis viewing).

In some configurations of the optical volume 140 (e.g., a rectangularprism of uniform index of refraction), this effect is less prominent atviewing angles off-axis (e.g., not perpendicular to the light source 110and optical volume 140), as shown in FIG. 7. This may result inseparation between on-angle and off-angle views, further enhancing thedepth effect enabled by stereoscopic images.

The display 100 may additionally include optical volume guides 141,which function to enhance the ‘floating’ effect of images within theoptical volume 140. The optical volume guides 141 are preferablymarkings visible on the optical volume 140 (or otherwise within theoptical path of the light source 110) that draw a viewer's eye to aid inproviding the sensation of depth to images of the display 100.

The optical volume guides 141 may be any visible two- orthree-dimensional structure present in a plane distinct from (andpreferably parallel to) the perceived plane locating a primary/on-axisimage viewed by a viewer. For example, the optical volume guides 141 maybe etched, painted, adhered, or printed onto the surface of the opticalvolume 140. Additionally or alternatively, the optical volume guides 141may be located on a separate light guide, substrate, or on any othercomponent.

In one implementation of an invention embodiment, the optical volumeguides 141 are reflective on at least one surface. In thisimplementation, the system 100 incorporates a reflective polarizer 130(or other reflective or partially reflective surface) 100 create avirtual image of the optical volume guides 141, creating the perceptionof a volume larger (e.g., twice as large) than the optical volume 140'soriginally perceived size, as shown in FIG. 8 (the optical volume 140'soriginally perceived size may be smaller than its actual size due to theuse of high-index material).

Note that the use of optical volume guides 141 may also enable thethree-dimensional effect of the display 100 to be better perceived in(two-dimensional) video recordings than other displays, allowing for thefull impact of display 100 to be better communicated over film.

The display 100 may additionally or alternatively use opaque elements(e.g., portions of an opaque housing) 100 surround or partially surroundsides of the optical volume 140, further enhancing the perception ofdepth (and potentially also reducing the presence of undesired light),as shown in FIG. 9A. Additional views of this example implementation areas shown in FIG. 9B and FIG. 9C (including optional optical volumeguides 141).

Likewise, the display 100 may be used with other displays too in anymanner (e.g., in a 2×2 or 3×3 array, back to back).

The onboard computer 150 functions to perform image processing for imagedata received by the display 100 prior to display by the light source110. For example, the onboard computer may separate 3D model informationinto slices to be projected by the light source 110. The onboardcomputer 150 may additionally or alternatively function to prepare 3Dimage data for voxel representation in any manner. For example, theonboard computer 150 may generate 2D stereoscopic views based on thestructure/configuration of the parallax generator 120. As anotherexample, if light folding is performed by the display 100 (i.e., imagesare sliced and anisotropically scaled), the onboard computer 150 mayperform interpolation between pixel values to determine a newtransformed pixel value. As another example, the onboard computer 150may perform dithering to simulate blurring at image edges. As a thirdexample, the onboard computer may send control commands (e.g., 100 thecontextual lighting system 160).

The onboard computer 150 may additionally or alternatively function tocontrol general properties of the light source 110 or of other aspectsof the display 100; for example, the onboard computer 150 may controlbrightness of light source 110 pixels to simulate changes of opacity ina displayed image.

Note that the functions described as performed by the onboard computer150 may additionally or alternatively be performed by another computersystem (e.g., a distributed computing system in the cloud).

In one implementation of an invention embodiment, the onboard computer150 is communicative with another electronic device (e.g., a smartphone,a tablet, a laptop computer, a desktop computer, etc.) over a wiredand/or wireless communication connection. In this implementation, datamay be streamed or otherwise communicated between the onboard computer150 and the other electronic device. For example, a smartphone maytransmit video information to the onboard computer, where it is slicedinto depth slices by the onboard computer 150. Additionally oralternatively, depth slicing may be performed by the other electronicdevice. In general, the task of image processing may be performed and/orsplit between any number of electronic devices communicative with theonboard computer 150.

The contextual lighting system 160 functions to light the periphery ofthe display 100 (or nearby area) with a light meant to match or resemblelighting conditions programmed into digital imagery displayed by thedisplay 100. By doing so, the contextual lighting system 160 can ‘lock’the imagery in the real world for some users; for example, a user's handmay be lit to match the lighting of a particular part of a digital scenenear the user's hand. This may substantially increase immersiveness.

The contextual lighting system 160 may control lighting properties(e.g., color, duration, intensity, direction, degree of focus,collimation, etc.) based on explicit instructions in the digitalimagery. Additionally or alternatively, the contextual lighting system160 may control lighting properties in any manner. For example, thecontextual lighting system 160 may (for digital images without explicitcontextual lighting instructions) average the color across a subset ofan image and light the display 100 with this light.

The contextual lighting system 160 may include any number and/or type oflighting devices; for example, color controllable LEDs.

The contextual lighting system 160 is preferably controlled by theonboard computer 150, but may additionally or alternatively becontrolled by any controller or computer system.

The display 100 may also include means for interaction tracking. Forexample, the display 100 may include a depth camera that tracks userinteraction with the display 100, allowing control and/or manipulationof the image displayed based on hand gestures and/or other interactionbetween a viewer and the display 100 as measured by the depth camera. Asanother example, the display 100 may include a transparent touch sensorthat tracks viewer touch interactions on surfaces of the display 100.

In one implementation of a preferred embodiment, the display 100includes an ultrasonic haptic feedback module and a head tracker (e.g.,a camera or other device that tracks head position, orientation, and/ormotion). In this implementation, tactile feedback via the hapticfeedback module may be modified according to head tracking data (orother data, e.g., hand tracking data, body tracking data, video/audiocapture data, etc.). Tactile feedback may also be provided by hapticgloves that are coordinated through the onboard computer 150 to providedtactile feedback that is coincident with the visual feedback of thesystem.

In another implementation of a preferred embodiment, the display 100includes an infrared-opaque wand for interaction with aerial display(e.g., the wand is air gap or water containing, or of an IR blocking butvisible-light transparent plastic or glass). This wand functions as aninteraction instrument (in addition to a user's bare hands) that can beread by a depth camera, but which does not block the light of the aerialimage like a visible-light interaction instrument or a hand would, inthe case of interaction that extends past the plane of the aerial image.Additionally or alternatively, the wand may feature an infraredreflector and/or light emitter to better enable tracking. In someexample, the wand may include internal gyros and accelerometers toprovide six degree-of-freedom tracking.

The display 100 may additionally or alternatively include voice control(e.g., via an automated assistant such as Amazon's Alexa).

Tracking and interaction are preferably controlled by the onboardcomputer 150, but may additionally or alternatively be controlled by anycontroller or computer system.

Note that while the components of the display 100 are shown inparticular configurations, it is understood the that components of thedisplay 100 may be coupled/ordered in any manner to produce the effectsas described in the present application.

2. Superstereoscopic Display Image Processing

In traditional stereoscopic displays, the display is typically optimizedfor a fixed number of viewers at a set distance. For example, in atraditional stereoscopic display featuring a lenticular lens, a viewermust remain within a bounded volume (both in terms of viewing distance,along the viewing axis, and distance perpendicular to the viewing axis).This is a huge disadvantage to these systems. With the advent of headtracking (or other mechanism to infer the location of a user's eyes asthey move in space), some stereoscopic displays modify the projectedimage to extend the viewing volume.

The display 100 is able to address this issue in a substantially morerobust manner. For example, the display 100 may compensate for viewingdistance (as determined by a head tracker or other mechanism fordetermining the distance of a viewer from the display 100, such as acamera) by modifying the image projected to the parallax generator 120(and/or by modifying the optical properties of the parallax generator120 itself) at the onboard computer 150 (or otherwise). Viewing distanceis important because the light projected by a lenticular lens followsconstant angle (so the lateral space between rays increases with viewingdistance). An example of this is as shown in FIGS. 10A and 10B. At afirst viewing distance, a user may perceive a first image (e.g.,corresponding to pixel columns 0, 10, 20, etc.) with one eye and asecond image with the other eye (e.g., corresponding to pixel columns 1,11, 21, etc.). This is similar to viewing a traditional lenticularlens-based stereoscopic display at optimal viewing distance. At asecond, closer, distance, the user may perceive several images with eacheye (as the lateral distance between views is closer). For example, auser may perceive three images (e.g., corresponding to 0, 10, 20 . . . ;1, 11, 21 . . . ; 2, 12, 22) with a first eye and three images (e.g.,corresponding to 2, 12, 22 . . . ; 3, 13, 23 . . . ; 4, 14, 22) with asecond eye—note that the images may overlap at close distances. Thedisplay 100 is capable of adapting to this change in viewing angle inone or more ways. For instance, the display 100 may dim or turn offpixel columns that would appear brightly to both eyes of an individualviewer. Even if views do not overlap, note that in the closer viewingdistance each eye is capable of seeing more pixels. The display 100 mayadapt to this in any of several manners; for example, the display 100may increase the resolution of a displayed image without changing thepictured scene, either via interpolation, by selecting ahigher-resolution source, or if the image is generated in real-time,changing the resolution of the generated image. Another issue withchanging viewing distance is that the lenticular lens may noticeablydistort images (e.g., stretching them horizontally or otherwise changingaspect ratio) in a viewing-distance dependent manner. The display 100may adapt to this issue by rescaling the displayed image eithervertically or horizontally to correct the perceived aspect ratio by aviewer at a set distance.

Note also that viewing distance affects perceived depth (due todifferences in separation of the stereoscopic images); the display 100may additionally or alternatively modify image output to preserve agiven depth perception.

To the extent that the parallax generator 120 varies views horizontally(e.g., as with a columnar lenticular lens), it may also be desirable tomodify views displayed by the display 100 to reflect vertical movement(e.g., a user changing viewing height). The display 100 may do this bydetecting a y-axis viewing disparity (e.g., a viewing height relative tosome reference) and changing the perspective of the displayed imageaccordingly. For example, a user with a viewing height above a referencemight see a scene from a slightly elevated angle, whereas when that usersquats the user might see the scene from an even or depressed angle. Ifthe display 100 is generating the view in real time from a 3D source,this may be as simple as changing the 2D output of the light source 110to reflect the change in angle. If the source is limited in possibleperspectives, the display too may additionally or alternatively distortthe 2D output of the light source 110 to simulate a change in elevationbased on user viewing height.

These are examples of accommodations that the display 100 can make whentracking a user's head. The display 100 may additionally track multipleviewers at the same time. In some senses this is similar to thesingle-user case—just as “views” (distinct images projected at differentangles) may be allocated to a single user's eyes dependent on viewingdistance, they may in general be allocated to multiple users. In thesingle user case, a primary concern with views generally outside ofperception is cross-talk—i.e., that users may see images not intended toreach their eyes (because they are off-angle). While ghost images aretypically dimmer than primary images (those intended to reach a user'seyes) they may still cause blurring. In the single user case, it may bepossible simply to turn off views that cause ghosting (or to timemultiplex views that are reaching a viewer's eyes). This may still bepossible in the multi-user case as well, but the “ghost” views for oneperson may be the primary views for another, and thus this is a highercomplexity issue. Another primary concern with views is the distinctionbetween “natural” and “artificial” views. As an individual moves his orhead laterally, the user sees sequentially different views (even thoughthese views may be identical)—this is a function of the lenticularlens—but eventually the views shown to the user repeat unless the lightoutput of the display 100 changes (due to an effect known as raycrossover). These views (those that exist without changing the lightoutput of the display 100) are “natural” views. Additionally, thedisplay 100 may modify the light output of the display 100 to provide acontinuous view even across the boundaries of “natural view” zones. Inother words, the display 100 may track (based on user viewing position)what views are shown to a user, and update display output as a userapproaches a view boundary. For example, in a lenticular lens that has aperiod of ten pixel columns, as the user approaches the tenth pixelcolumn, the display 100 may change the output of pixel column 1 toappear as “pixel column 11” (assuming the goal is to maintain acontinuous view around a scene).

This principle applies in the multi-user scenario as well, except thatviews are now divided across users (to the extent that different imagesneed to be shown to different users, such as if they are at differentviewing distances, viewing heights, or are intended to see differentcontent). The display 100 may divide views across multiple users in anymanner and may apply the various image refinement techniques discussedabove to views presented to these users in any manner.

The display 100 may additionally or alternatively smooth transitionsbetween applications of these image refinements. This may beparticularly important in the case of “view crash”, when one user,previously shown an image in a modified fashion (e.g., projected toprovide perception of a first viewing height) moves into the naturalview zone of another user being shown a different perspective of thatimage (e.g., projected to provide perception of a second, differentviewing height). In such a scenario, the display too may detect that aview crash is likely to occur, and may change the output presented toone or more users to (ideally) bring the views presented to differentusers to unity as the users' views “crash” (i.e., begin to intersect).

As another example of transition smoothing, the display 100 may damptransitions. This may be particularly useful in scenarios where headtracking produces erroneous values: transition damping may prevent viewsfrom rapidly changing if erroneous values occur. Also, if the display100 loses head tracking lock on a viewer, the display 100 may attempt toperform dead reckoning until lock is regained.

Additionally or alternatively, aspects of displayed images may bemodified based on environmental factors (e.g., temperature, humidity,altitude, etc.). Aspects of displayed images may also be modified tomaintain compatibility between images in implementations of the display100 featuring multiple light sources (e.g., as in an array of displays100).

Note that, as shown in FIG. 7, off-axis views in a high-index volume mayappear at different perceived depths (due to the different distancetraveled by light within the high-index volume with angle, at least fora non-radially-symmetric volume), so the image refinement techniquesabove (and display in general) may be additionally modified to accountfor the geometry and optical properties (particularly, index ofrefraction) of the high-index optical volume 140.

As a person skilled in the art will recognize from the previous detaileddescription and from the figures and claims, modifications and changescan be made to the preferred embodiments of the invention withoutdeparting from the scope of this invention defined in the followingclaims.

We claim:
 1. A superstereoscopic display with enhanced off-angleseparation comprising: a first light source; a lenticular lens opticallycoupled to the first light source that, with the first light source,generates a first light output having viewing angle dependency; and ahigh-index optical volume optically coupled to the lenticular lens;wherein the optical volume has an index of refraction greater than one;and a tracking sensor, wherein the first light source modifies the firstlight output to enable superstereoscopic viewing of the firstthree-dimensional image for a first viewer based on at least one of headtracking data and eye tracking data, the at least one of head trackingdata and eye tracking data corresponding to the first viewer andcaptured by the tracking sensor; wherein the first light sourcetransmits the first light output to the high-index optical volume;wherein the high-index optical volume transmits the first light outputto free-space; wherein, after transmission by the high-index opticalvolume, the first light output comprises a first visible image at afirst viewing angle and a second visible image, non-identical to thefirst visible image, at a second viewing angle separated by a firstnon-zero angle from the first viewing angle, and a third visible imagenon-identical to the first and second visible images, at a third viewingangle separated by a second non-zero angle from the second viewingangle; wherein the first, second, and third visible images correspond toviews of a first three-dimensional image and enable superstereoscopicviewing of the first three-dimensional image; wherein the first lightsource further modifies the first light output in response to the firstviewer moving closer to the display by performing at least one of:modifying the first light output to reduce view ghosting in response tothe first viewer moving closer to the display, modifying the first lightoutput to correct for aspect ratio distortion in response to the firstviewer moving closer to the display, and modifying the first lightoutput to correct for depth perception change in response to the firstviewer moving closer to the display.
 2. The superstereoscopic display ofclaim 1, wherein the first light source further modifies the first lightoutput to reduce view ghosting in response to the first viewer movingcloser to the display.
 3. The superstereoscopic display of claim 2,wherein the first light source damps modifications of the first lightoutput in response to changes in head or eye tracking data.
 4. Thesuperstereoscopic display of claim 1, wherein the first light sourcefurther modifies the first light output to correct for aspect ratiodistortion in response to the first viewer moving closer to the display.5. The superstereoscopic display of claim 4, wherein the first lightsource damps modifications of the first light output in response tochanges in head or eye tracking data.
 6. The superstereoscopic displayof claim 1, wherein the first light source further modifies the firstlight output to correct for depth perception change in response to thefirst viewer moving closer to the display.
 7. The superstereoscopicdisplay of claim 6, wherein the first light source damps modificationsof the first light output in response to changes in head or eye trackingdata.
 8. The superstereoscopic display of claim 1, wherein thehigh-index optical volume decreases the perceived viewing distance ofthe first, second, and third visible images such that the first, second,and third visible images appear to be located within the high-indexoptical volume.
 9. The superstereoscopic display of claim 8, furthercomprising a set of optical volume guides located at a first surface ofthe high-index optical volume; wherein the set of optical volume guidesenhances depth perception of images displayed by the display.
 10. Thesuperstereoscopic display of claim 9, wherein the optical volume guidesare painted on, adhered to, etched into, or printed on a surface of thehigh-index optical volume.
 7. The superstereoscopic display of claim 1,wherein the lenticular lens is a one-dimensional lenticular lensparallel to addressable columns of the first light source; wherein theone-dimensional lenticular lens is perpendicular to addressable rows ofthe first light source.
 8. The superstereoscopic display of claim 7,wherein the lenticular lens is a one-dimensional lenticular lensoriented at an angle of more than zero but less than ninety degreesrelative to addressable columns of the first light source, resulting inapportionment of resolution loss across both the addressable columns andaddressable rows of the first light source.
 9. The superstereoscopicdisplay of claim 7, wherein the lenticular lens is a two dimensionallenticular lens resulting from stacking two one-dimensional lenticularlenses.
 10. A superstereoscopic display with enhanced off-angleseparation comprising: a first light source; a lenticular lens opticallycoupled to the first light source that, with the first light source,generates a first light output having viewing angle dependency; and ahigh-index optical volume optically coupled to the lenticular lens;wherein the optical volume has an index of refraction greater than one;and a tracking sensor, wherein the first light source modifies the firstlight output to enable superstereoscopic viewing of the firstthree-dimensional image for a first viewer and a second viewer based onat least one of head tracking data and eye tracking data, the at leastone of head tracking data and eye tracking data corresponding to thefirst and second viewers and captured by the tracking sensor; whereinthe first light source transmits the first light output to thehigh-index optical volume; wherein the high-index optical volumetransmits the first light output to free-space; wherein, aftertransmission by the high-index optical volume, the first light outputcomprises a first visible image at a first viewing angle and a secondvisible image, non-identical to the first visible image, at a secondviewing angle separated by a first non-zero angle from the first viewingangle, and a third visible image non-identical to the first and secondvisible images, at a third viewing angle separated by a second non-zeroangle from the second viewing angle; wherein the first, second, andthird visible images correspond to views of a first three-dimensionalimage and enable superstereoscopic viewing of the firstthree-dimensional image.
 11. The superstereoscopic display of claim 10,wherein the first light source modifies the first light output to enablesuperstereoscopic viewing of the first three-dimensional image for thefirst viewer; wherein the first light source modifies the first lightoutput to enable superstereoscopic viewing of a second three-dimensionalimage for the second viewer.
 12. The superstereoscopic display of claim11, wherein the first and second three-dimensional images are identical.13. The superstereoscopic display of claim 12, wherein the first lightsource modifies the first light output to provide a first perspective ofthe first three-dimensional image to the first viewer based upon aviewing angle, viewing distance, and viewing height of the first viewer.13. The superstereoscopic display of claim 12, wherein the first lightsource modifies the first light output to provide a second perspectiveof the first three-dimensional image to the second viewer based upon aviewing angle, viewing distance, and viewing height of the secondviewer; wherein the first and second perspectives are non-identical. 14.The superstereoscopic display of claim 13, wherein the first lightsource initially modifies the first light output such that the firstperspective is modified to reflect a first viewing height of the firstviewer and such that the second perspective is modified to reflect asecond viewing height of the second viewer; wherein the first and secondviewing heights are nonidentical.
 15. The superstereoscopic display ofclaim 14, wherein the first light source later modifies the first lightoutput such that both of the first and second perspectives reflect thefirst viewing height of the first viewer in response to the secondviewer moving toward the first viewer.
 16. The superstereoscopic displayof claim 10, wherein the first light source further modifies the firstlight output in response to the first viewer moving closer to thedisplay by performing at least one of: modifying the first light outputto reduce view ghosting in response to the first viewer moving closer tothe display, modifying the first light output to correct for aspectratio distortion in response to the first viewer moving closer to thedisplay, and modifying the first light output to correct for depthperception change in response to the first viewer moving closer to thedisplay.
 17. The superstereoscopic display of claim 16, wherein thefirst light source further modifies the first light output to reduceview ghosting in response to the first viewer moving closer to thedisplay.
 18. The superstereoscopic display of claim 17, wherein thefirst light source damps modifications of the first light output inresponse to changes in head or eye tracking data.
 19. Thesuperstereoscopic display of claim 16, wherein the first light sourcefurther modifies the first light output to correct for aspect ratiodistortion in response to the first viewer moving closer to the display.20. The superstereoscopic display of claim 19, wherein the first lightsource damps modifications of the first light output in response tochanges in head or eye tracking data.
 21. The superstereoscopic displayof claim 16, wherein the first light source further modifies the firstlight output to correct for depth perception change in response to thefirst viewer moving closer to the display.
 22. The superstereoscopicdisplay of claim 21, wherein the first light source damps modificationsof the first light output in response to changes in head or eye trackingdata.
 23. The superstereoscopic display of claim 10, wherein thehigh-index optical volume decreases the perceived viewing distance ofthe first, second, and third visible images such that the first, second,and third visible images appear to be located within the high-indexoptical volume.
 24. The superstereoscopic display of claim 23, furthercomprising a set of optical volume guides located at a first surface ofthe high-index optical volume; wherein the set of optical volume guidesenhances depth perception of images displayed by the display.
 25. Thesuperstereoscopic display of claim 24, wherein the optical volume guidesare painted on, adhered to, etched into, or printed on a surface of thehigh-index optical volume.
 26. The superstereoscopic display of claim10, wherein the lenticular lens is a one-dimensional lenticular lensparallel to addressable columns of the first light source; wherein theone-dimensional lenticular lens is perpendicular to addressable rows ofthe first light source.
 27. The superstereoscopic display of claim 26,wherein the lenticular lens is a one-dimensional lenticular lensoriented at an angle of more than zero but less than ninety degreesrelative to addressable columns of the first light source, resulting inapportionment of resolution loss across both the addressable columns andaddressable rows of the first light source.
 28. The superstereoscopicdisplay of claim 26, wherein the lenticular lens is a two dimensionallenticular lens resulting from stacking two one-dimensional lenticularlenses.